Someone asked me and I don't know. Do they dim quantised or continuous, eg
1/2, 1/4, 1/8 with an existing lamp dimmer control, do they flicker on lower setting? what colour do they emit at (if possible) 10 percent of full rating? At 10 percent is overall power consumption more than an incandescent at 10 percent? . Comfortable pinkish /orange at that level for conventional bulb 100W run at 10W or so.
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
You sure ask a lot of questions for someone from Jersey.
Several years ago I bought a GE dimmable CFL, which I never installed. (Still sitting there.)
What do you mean by a "conventional" dimmer" -- a rheostat? Once you get below a certain voltage, the lamp will shut off, whether or not it "dims".
The common type of dimmer in the US uses PWM. The Scottish-invented X10 is the best example of this design. The X10 has 255 levels, but the GE dimmable CFL works with only the first top 10 or so. The light gets dimmer, then goes out abruptly. You don't have the range available with incandescent lamps.
I don't remember the color changing at all. It's controlled by the laws of quantum mechanics, not the line voltage, so it shouldn't change. I don't remember it flickering, either.
As for power savings... You can't meaningfully compare tungsten lamps running at x% with fluorescent lamps running at x%.Tungsten lamps get less efficient (that is, the percentage of electricity they convert into /visible/ light drops) as the voltage drops. If you "always" dim a particular incandescent light, you should replace it with a smaller lamp you don't need to dim. This will use less electricity.
(If this isn't clear... A 100W bulb running at 50W produces less light than a 50W bulb.)
By the way, tungsten-halogen lamps should not be dimmed "just a bit". If the filament runs at a temperature slightly below the point at which the halgoen reaction starts, the bulb will burn out prematurely. (I've seen this.) Halogen bulbs should be dimmed "substantially".
Was researching this the other day. The makers of 'dimmable' CFLs recommend only certain dimmers (PWM), and do not recommend other systems based on older technology.
Since color is based on the phospor's visiable light spectrum, I doubt that will change much at all...
Many years ago, probably 8-9 years, I converted the 500 watt halogen pole light to 100 watt equiv. CFL drawing 23 watts or so. I used the same dimmer. The CFL was $20 at the store. It worked great. The color temperature was very good in that it appeared more halogen than halogen. Many CFL's take some time to gain brightness as it heats. On a lower setting it will take longer. It will go to minimum brightness after setting to a higher level then reducing. I saw no change in color temperature with brightness, but color temperature may will vary on warm up.
The (dimmable) CFL's sold here (US) are not really comparable to incandescents. Their "briteness range" is probably something like 60% to 100% corresponding to 20% to 100% of the range of a "traditional" dimmer. Within that operating range, their output *appears* to be continuously variable (i.e., no noticeable steps in intensity)
Color temperature is largely unchanged over that range.
Intensity varies with time as the lamps take a while to get up to operating temperature (?).
At the dimmer's lowest setting, the lamps don't appear to start at all (at least not in any realistic time frame).
Our (personal) experience has found them to be very disappointing. We've switched back to incandescents in all of the dimmer applications in the house as it is just not possible to get a very *low* level of light out of the CFL's.
pwehaps for a fully dimmable situation you have to buy dimmer and bulb as one package, 50 percent dimming is not what this person is after. Looks as though they will have to stay with incandescents for that reason and they like the orange/yellow/pink colouration at low levels
Dunno. We certainly aren't going to go through the house replacing all of our "dimmers" (each with a "three way" switch built in) just to accommodate CFL's. Presumably, someone will "fix" this problem in the future...
Yup, that is the approach we have taken. Our lights are placed such that on the lowest dimmer setting, there is
*just* enough light to see the general contents of the room when it is pitch black outdoors. I.e., perfect for waking up in the middle of the night and *not* wanting to shock your eyes with an overly bright light (the CFLs at their lowest visible setting are *way* too bright for this purpose). This is ideal for house guests who might be unfamiliar with the layout of the house and who could benefit from our leaving the lights "on, dim" at bedtime.
I have dimmable fluorescents lighting my kitchen worktops which required special (expensive) ballasts. The actual dimmer control just handles low volt DC. They work beautifully giving near the same range as incandescent. So my guess is dimming CFLs via a standard dimmer is going to be a cludge. Think to do the job properly without adding wiring would need special CFLs and a special dimmer which sent control signals via the wiring.
--
*Time is what keeps everything from happening at once.
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
And how do you justify the costs of having a licensed electrician come in and add *those* second *circuits*? Followed by the drywall man to clean up the (cosmetic) mess he leaves? Followed by the painter? Easier to spend that money inefficently heating tungsten for the next five (?) years -- until a genuine dimmable CFL comes along! :>
Activities at night either want subdued lighting (e.g., relaxing, listening to music, watching TV, etc.) *or* take place in locations where lights are never dimmed and, thus, use regular CFLs. For example, working at the computer, cooking dinner (kinda hard to do this in "dim light" :> ), reading, etc.
We had considered putting smaller (wattage) lamps in those locations but then you are always stuck with too little light.
It won't be long before the market's complaints about dimmable CFLs cause manufacturers to come up with a viable "screw in" replacement for incandescents with *conventional* dimmers.
Why not? With enough smarts, you could excite it at 2 or 3 times the line frequency -- but very low duty cycles...? I think it is just a question of waiting for the electronics/magnetics to get small enough on a practical scale.
E.g., years ago, the idea of a 500W, multiple output power supply fitting in a ~30 cu in volume would have been unheard of... yet now you can buy them for the price of an expensive lunch! :-/
I would say at least 1/10 the brightness or more when I have done CFL dimming. For dim lighting the choice is obvious. Install a separate led lighting system. It can stay on all the time and have battery backup.
Its not mysterious. The small leds as shown in the article are easy to overdrive and get very fast droop, and then permanent droop. They even change color as they start to burn up.
The specs don't usualy say lm/watt they give lumens at some wattage, usually 1. If you decrease current, you get more lm/watt of course.
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